Integrating environmental sustainability in clinical counselling: a randomised, double-blind, experimental vignette...

Integrating environmental sustainability in health-care decision making might be a key strategy to achieve greener clinical practice. We aim to explore whether advising environmentally sustainable treatment options with or without explicitly mentioning sustainability as an argument in clinical counselling affects patients' trust in care, compared with less sustainable standard treatment options, while accounting for differences in severity and types of medical problems.

This randomised, double-blind, experimental vignette study was conducted at the Leiden University Medical Center (Leiden, Netherlands). We recruited a representative sample (based on sex, age, education level, and geographical distribution) of the general Dutch adult population. Participants were masked, randomised, and allocated to one of the eight study groups (four types of advice × two levels of severity) using automatic online software. We used an online survey tool to provide participants with five short descriptions (vignettes) of hypothetical patient-physician interactions based on their allocation to high severity or low severity scenarios and their physician's type of advice; varying in the level of environmental sustainability and whether sustainability is mentioned explicitly. Low severity scenarios described a general practice setting and high severity scenarios described a hospital setting where the patient had been referred. The primary outcome was a practice-based composite score labelled as trust in care (seven-point Likert scale from 1 [strongly disagree] to 7 [strongly agree]).

Between May 16 and 31, 2024, 2694 participants were invited to participate, of whom 1536 were included in the final sample size of the study. The mean age of participants was 51·7 years (SD 17·1). 762 (50%) participants were female and 774 (50%) were male. Participants receiving the Less Sustainable advice (mean 5·6 [SD 1·2]) generally had higher trust scores than participants receiving one of the other three types of advice (p<0·0001). Participants receiving the Sustainable made Explicit advice (mean 4·8 [1·6]) generally had lower trust scores than those receiving one of the other three types of advice (p<0·0001). Post-hoc analysis indicated that differences in trust scores were primarily driven by high severity conditions and varied across medical problems.

Advising more sustainable treatment options for low severity scenarios generally does not affect patients' trust in care, including when sustainability is mentioned explicitly. For high severity scenarios, advising more sustainable treatment options might negatively affect patients' trust; however, the size and presence of the observed effect varied across medical problems.

Leiden University.